Introduction: Studies have found pain and inflammation in the shoulder region of working sled dogs, and as skijoring involves pulling a weighted rider, the act of pulling in harness may result in injuries similar to those seen in sled dogs. The hypothesis is that the biceps brachii (BB) and triceps brachii (TB) muscles would work harder during skijoring as compared with a free-run.
Materials and Methods: Five privately owned, sound, skijoring dogs completed a free-run and a skijoring trial on the same flat trail in random order. Acoustic myography, measuring efficiency (E-score), spatial summation (S-score) and temporal summation (T-score) of the BB and TB was performed. Statistical analyses included Shapiro–Wilk tests and Student's t-tests. Significance was set at p-value less than 0.05.
Results: During the initial five seconds of recording from a standing start, the BB had significantly lower spatial summation (higher S score) while skijoring, compared with that of free running (p = 0.003). Temporal summation data for the BB showed a significantly lower frequency of fibre recruitment (higher T score) in the free-running task when compared with skijoring during the initial 5 seconds (p = 0.02). On the 600-foot section of flat trail at constant speed, TB action during skijoring showed significantly lower spatial summation (higher S score) than the free-run (p = 0.01).
Discussion/Conclusion: The BB and TB appear to work differently during skijoring and free-running tasks. With the increased frequency of muscle fibre recruitment in the BB at the start of skijoring compared with the free run, this muscle may be more likely to fatigue when skijoring.
Acknowledgments:
AMG device provided by CURO and Adrian P Harrison.
